Cerebrospinal fluid formation and absorption in dehydrated sheep

1998 ◽  
Vol 275 (2) ◽  
pp. F235-F238 ◽  
Author(s):  
Adam Chodobski ◽  
Joanna Szmydynger-Chodobska ◽  
Michael J. McKinley
Keyword(s):  
Cerebrospinal Fluid ◽  
Adaptive Response ◽  
Venous Pressure ◽  
Extracellular Fluid ◽  
Cerebral Ventricles ◽  
Central Venous ◽  
Ventriculocisternal Perfusion ◽  
Fluid Formation ◽  
The Brain ◽  
Csf Production

Cerebrospinal fluid (CSF) plays an important role in the brain’s adaptive response to acute osmotic disturbances. In the present experiments, the effect of 48-h dehydration on CSF formation and absorption rates was studied in conscious adult sheep. Animals had cannulas chronically implanted into the lateral cerebral ventricles and cisterna magna to enable the ventriculocisternal perfusion. A 48-h water deprivation altered neither CSF production nor resistance to CSF absorption. However, in the water-depleted sheep, intraventricular pressure tended to be lower than that found under control conditions. This likely resulted from decreased extracellular fluid volume and a subsequent drop in central venous pressure occurring in dehydrated animals. In conclusion, our findings provide evidence for the maintenance of CSF production during mild dehydration, which may play a role in the regulation of fluid balance in the brain during chronic hyperosmotic stress.

Effect of systemic arterial hypotension on the rate of cerebrospinal fluid formation in dogs

1974 ◽  
Vol 41 (3) ◽  
pp. 350-355 ◽  
Author(s):  
Michael E. Carey ◽  
A. Richard Vela
Keyword(s):  
Blood Pressure ◽  
Cerebrospinal Fluid ◽  
Mean Arterial Blood Pressure ◽  
Content Type ◽  
Arterial Blood ◽  
Ventriculocisternal Perfusion ◽  
Fluid Formation ◽  
The Mean ◽  
Csf Production ◽  
Fine Print

✓The rate of cerebrospinal fluid (CSF) production in dogs was measured by ventriculocisternal perfusion with artificial CSF containing inulin. In normotensive animals, the average CSF production was 36 ± 6 µl/min. When the mean arterial blood pressure was reduced to 62 ± 1 mm Hg, the CSF production fell to 22 ± 5 µl/min, a 39% reduction in fluid formation. The authors briefly discuss various hypotheses to explain this reduction.

scholarly journals Kinetics of a nucleoside release from lactide-caprolactone and lactide-glycolide polymers in vitro.

2000 ◽  
Vol 47 (1) ◽  
pp. 59-64
Author(s):  
T Kryczka ◽  
P Grieb ◽  
M Bero ◽  
J Kasperczyk ◽  
P Dobrzynski
Keyword(s):  
Formation Rate ◽  
Local Treatment ◽  
Extracellular Fluid ◽  
Brain Extracellular Fluid ◽  
Artificial Cerebrospinal Fluid ◽  
Fluid Formation ◽  
Further Development ◽  
Kinetics Of ◽  
The Brain

We assessed the rate of release of a model nucleoside (adenosine, 5%, w/w) from nine different lactide-glycolide or lactide-caprolactone polymers. The polymer discs were eluted every second day with an artificial cerebrospinal fluid at the elution rate roughly approximating the brain extracellular fluid formation rate. Adenosine in eluate samples was assayed by HPLC. Three polymers exhibited a relatively constant release of adenosine for over four weeks, resulting in micromolar concentrations of nucleoside in the eluate. This points to the necessity of further development of polymers of this types as intracerebral nucleoside delivery systems for local treatment of brain tumors.

scholarly journals Thyroid Transcription Factor-1 Facilitates Cerebrospinal Fluid Formation by Regulating Aquaporin-1 Synthesis in the Brain

2007 ◽  
Vol 282 (20) ◽  
pp. 14923-14931 ◽  
Author(s):  
Jae Geun Kim ◽  
Young June Son ◽  
Chang Ho Yun ◽  
Young Il Kim ◽  
Il Seong Nam-goong ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Transcription Factor ◽  
Aquaporin 1 ◽  
Thyroid Transcription Factor 1 ◽  
Thyroid Transcription Factor ◽  
Fluid Formation ◽  
Transcription Factor 1 ◽  
The Brain

Potassium exchange between cerebrospinal fluid, plasma, and brain

1965 ◽  
Vol 209 (6) ◽  
pp. 1219-1226 ◽  
Author(s):  
Helen Cserr
Keyword(s):  
Cerebrospinal Fluid ◽  
Specific Activity ◽  
Potassium Concentration ◽  
Extracellular Fluid ◽  
Ionic Fluxes ◽  
Ventriculocisternal Perfusion ◽  
Anesthetized Dogs ◽  
The Relationship ◽  
Potassium Exchange ◽  
Total Potassium

Potassium exchange between cerebrospinal fluid (CSF), plasma, and brain was investigated in anesthetized dogs and rats using the technique of ventriculocisternal perfusion. Transport via bulk secretion and absorption of CSF accounts for only 20% of total potassium exchange, unidirectional ionic fluxes across the ependyma for 80%. This large transependymal exchange is primarily between CSF and brain intracellular potassium pools, since two-thirds of the K42 outflux can be recovered from brain tissue. Conversely, much of transependymal influx comes from brain, as demonstrated by the low specific activity of influx relative to that of plasma following intravenous injection of K42. Potassium outflux is almost proportional to CSF [K+] in the range 0–10 mEq/liter but is independent of plasma [K+]. Perfusion with 10–5 m ouabain reduces transependymal K42 outflux to 25% of control; the residual outflux may be accounted for by passive processes. Results are discussed in terms of 1) regulation of CSF potassium concentration and 2) the relationship between CSF and brain extracellular fluid.

Acute effect of glycerol on net cerebrospinal fluid production in dogs

1985 ◽  
Vol 63 (5) ◽  
pp. 759-762 ◽  
Author(s):  
Huda Y. Zoghbi ◽  
Sada Okumura ◽  
John P. Laurent ◽  
Marvin A. Fishman
Keyword(s):  
Cerebrospinal Fluid ◽  
Acute Effect ◽  
Serum Osmolality ◽  
Percentage Change ◽  
Perfusion Technique ◽  
Content Type ◽  
Ventriculocisternal Perfusion ◽  
Fluid Production ◽  
The Mean ◽  
Csf Production

✓ The effect of glycerol administration on cerebrospinal fluid (CSF) formation in dogs was studied by means of a ventriculocisternal perfusion technique. Net CSF production rate decreased after oral administration of glycerol (3 gm/kg) from a baseline level of 42.33 ± 6.68 µl/min (mean ± standard error) to a trough of 10.33 ± 4.88 µl/min at 90 minutes after administration (p < 0.025). Serum osmolality concomitantly increased from a baseline value of 296 ± 2.83 to 309 ± 4.7 mOsm/kg H2O at 90 minutes. The mean percentage change in CSF production inversely correlated to the mean percentage change in serum osmolality, r = −0.85. Thus, glycerol administration decreases net CSF formation, and this effect may be related in part to the rise in serum osmolality.

Role of active transport of chloride in formation of dogfish cerebrospinal fluid

1960 ◽  
Vol 199 (1) ◽  
pp. 124-126 ◽  
Author(s):  
C. Adrian M. Hogben ◽  
Per Wistrand ◽  
Thomas H. Maren
Keyword(s):  
Cerebrospinal Fluid ◽  
Steady State ◽  
Active Transport ◽  
Aqueous Humor ◽  
Extracellular Fluid ◽  
Chloride Concentration ◽  
Potential Difference ◽  
Fluid Formation

A significant steady state or d.c. potential difference exists between the cerebrospinal and extracellular fluids of the anesthetized dogfish. Since the cerebrospinal fluid is negative with respect to the extracellular fluid and the chloride concentration is greater in cerebrospinal fluid, the formation of cerebrospinal fluid must involve at least one process: active transport of Cl–. While acetazolamide abolishes the gradient of chloride between dogfish cerebrospinal fluid and plasma, its administration did not demonstrably change the potential difference. Though the active transport of Cl– is clearly part of the process of cerebrospinal fluid formation, it is probably only part of the process. No potential difference was observed between dogfish aqueous humor and extracellular fluid.

Exchange of calcium between blood, brain, and cerebrospinal fluid

1965 ◽  
Vol 208 (6) ◽  
pp. 1058-1064 ◽  
Author(s):  
Leonard Graziani ◽  
Anthony Escriva ◽  
Robert Katzman
Keyword(s):  
Cerebrospinal Fluid ◽  
Steady State ◽  
Brain Tissue ◽  
Specific Activity ◽  
Ventricular System ◽  
Passive Diffusion ◽  
Bulk Fluid ◽  
Fluid Formation ◽  
The Brain ◽  
Rate Of Movement

Ca exchange was measured in anesthetized cats during steady-state ventriculocisternal perfusions. When Ca45 was added to the perfusate the efflux coefficient from CSF averaged 0.025 ml/min of CSF cleared of Ca45. This coefficient was independent of CSF Ca concentration, indicating passive diffusion. About onethird of this isotope was recovered in brain tissue, two-thirds presumably diffused into blood. The brain radioactivity was localized to areas immediately adjacent to the CSF pathway. When the isotope was given systemically, the efflux coefficient into the ventricular system averaged 0.015 ml/min of serum effectively cleared of Ca45. In these experiments the specific activity of the CSF approached that of the serum. At the same time the specific activity of the brain Ca was low. Hence, the chief source of the Ca entering CSF must be blood. The rate of movement of Ca45 from blood to CSF was not altered when CSF formation was suppressed by adding acetazolamide or lowering the pH of the perfusate. This suggests that Ca transport is independent of the bulk fluid formation.

Effect of certain drugs on cerebrospinal fluid production in the dog

1964 ◽  
Vol 206 (2) ◽  
pp. 247-250 ◽  
Author(s):  
W. W. Oppelt ◽  
C. S. Patlak ◽  
D. P. Rall
Keyword(s):  
Cerebrospinal Fluid ◽  
Carbonic Anhydrase ◽  
Production Rate ◽  
Cardiac Glycoside ◽  
Intrathecal Administration ◽  
Production Rates ◽  
Ventriculocisternal Perfusion ◽  
Fluid Production ◽  
Significant Change ◽  
Csf Production

Cerebrospinal fluid (CSF) production rates were measured in the dog by ventriculocisternal perfusion with inulin containing buffer. Normal CSF production rate was found to be about 0.05 ml/min which represents a turnover of 0.4%/min. After intravenous administration of the carbonic anhydrase inhibitors, acetazolamide and methazolamide, a 40–50% decrease in CSF production occurred. An increase in plasma pCO2, by allowing the animals to inhale 95% oxygen, 5% CO2, did not result in any significant change in CSF production. Both intravenous and intrathecal administration of varying doses of the cardiac glycoside, ouabain, did not cause any significant change in CSF production rates. It is concluded that CSF production, in part, is controlled by a carbonic anhydrase system.

scholarly journals High versus low ultrafiltration rates during experimental peritoneal dialysis in rats: Acute effects on plasma volume and systemic haemodynamics

2022 ◽  
pp. 089686082110692
Author(s):  
Jakob Helman ◽  
Carl M Öberg
Keyword(s):  
Peritoneal Dialysis ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Central Venous Pressure ◽  
Plasma Volume ◽  
Venous Pressure ◽  
Extracellular Fluid ◽  
Extracellular Fluid Volume ◽  
Central Venous ◽  
Plasma Compartment

Introduction: Intradialytic hypotension is a common complication of haemodialysis, but uncommon in peritoneal dialysis (PD). This may be due to lower ultrafiltration rates in PD compared to haemodialysis, allowing for sufficient refilling of the blood plasma compartment from the interstitial volume, but the underlying mechanisms are unknown. Here we assessed plasma volume and hemodynamic alterations during experimental PD with high versus low ultrafiltration rates. Methods: Experiments were conducted in two groups of healthy Sprague-Dawley rats: one group with a high ultrafiltration rate ( N = 7) induced by 8.5% glucose and a low UF group ( N = 6; 1.5% glucose), with an initial assessment of the extracellular fluid volume, followed by 30 min PD with plasma volume measurements at baseline, 5, 10, 15 and 30 min. Mean arterial pressure, central venous pressure and heart rate were continuously monitored during the experiment. Results: No significant changes over time in plasma volume, mean arterial pressure or central venous pressure were detected during the course of the experiments, despite an ultrafiltration (UF) rate of 56 mL/h/kg in the high UF group. In the high UF group, a decrease in extracellular fluid volume of −7 mL (−10.7% (95% confidence interval: −13.8% to −7.6%)) was observed, in line with the average UF volume of 8.0 mL (standard deviation: 0.5 mL). Conclusion: Despite high UF rates, we found that plasma volumes were remarkably preserved in the present experiments, indicating effective refilling of the plasma compartment from interstitial tissues. Further studies should clarify which mechanisms preserve the plasma volume during high UF rates in PD.

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